The present invention is in the field of bio-effecting compositions and methods. More specifically, the present invention relates to compositions and methods of using the compositions to inhibit the growth of uterine fibroid cells.
Uterine Fibroids
Uterine fibroids (leiomyomata) are xe2x80x9cbenignxe2x80x9d tumors of the uterus, which occur in about 20 percent of women of reproductive age. Uterine fibroids are one of the most common tumors. Complications arising from uterine fibroids account for about 30% of all hysterectomies performed in the U.S., with a resulting direct cost of inpatient care of about $1 billion per year. Despite this enormous impact on women""s health, the factors causing formation and growth of these benign tumors remain largely enigmatic.
A uterine fibroid (leiomyomata) consists of a mass or population of smooth muscle cells and connective tissue that grows, usually slowly, within the uterine wall. Epidemiologic studies demonstrate that fibroids initially form after menarche. It is suspected that fibroid growth is due to a monoclonal, deregulated proliferation of uterine smooth muscle myometrial cells. The primary tumor cell type resulting from the growth of the fibroid are derived from myometrial cells and are referred to herein as leiomyoma cells. Uterine fibroid leiomyoma cells tend to proliferate during pregnancy and regress in menopause. Studies have clearly implicated gonadal steroids (estrogen and progesterone) as a likely factor in formation and growth of these benign tumors. This has motivated the search for therapies aiming at suppressing endogenous gonadal steroid production.
Treatment of Fibroids
Chemical intervention has focused on a class of compounds which previously had shown efficacy at reducing the circulating concentration of steroids and reducing myoma volume. These compounds are the Gonadotropin Releasing Hormone (GnRH) agonists: GnRHa. Other factors which have been implicated in stimulation of fibroid growth include Insulin-like Growth Factor-1 (IGF-1), Insulin, Growth Hormone, Epidermal Growth Factor (EGF), Transforming Growth Factor (TGF), and Basic Fibroblast Growth Factor (bFGF). However, chronic therapy with GnRHa has not gained widespread acceptance for the following reasons:
1. GnRHa is an expensive medication which generally must be given by injection.
2. The maximal effect of GnRH agonist is seen at 12 weeks, after which no further volume reduction is seen.
3. Although the median uterine volume reduction seen is about 50%, individual fibroids can vary greatly in response.
4. Rapid increases in both uterine and fibroid size are seen after discontinuation of therapy.
5. Chronic hypoestrogenemia, resulting from GnRH agonist use, causes osteoporosis, increased risk of heart disease, hot flashes, vaginal dryness, and mood swings. Some of these symptoms can be ameliorated by addition of daily low dose estrogen and progestin, which may compromise efficacy in some individuals and increases cost and complexity of therapy.
6. Present chemical interventions are administered systemically.
Surgical intervention in the treatment of fibroids can range from myomectomy to total hysterectomy, where the fallopian tubes and uterus are completely removed. As with all such surgeries, these treatments are extremely invasive. In addition to the risks generally associated with surgical interventions, infertility can result. However, in spite of the disadvantages of surgical intervention, the frequency of its use in the treatment of fibroids is indicative of the limitations of chemical intervention in relieving or controlling the condition in women.
Therefore, it would be beneficial to have a therapeutic option for the treatment of fibroids that is not invasive, as is surgery, and does not have the side effects of systemically administered hormonal therapies.
The present invention is the combination of compositions and methods for treating uterine fibroids by inhibiting the growth of uterine fibroid leiomyoma cells. The present invention uses non-hormonal compositions, and non-invasive or minimally-invasive delivery methods to non-systemically administer the compositions. The inhibition of cell growth involves the blocking of cell division and/or DNA replication in the target cells in order to retard the rate of increase of the cell population, to stabilize the cell population, or to reduce the number of cells in the cell population.
Myometrial cells are smooth muscle cells of the uterus. Leiomyoma cells are derived from myometrial cells, and are the tumor cell type which substantially comprise the population of cells of a uterine fibroid. A cell population, for the purpose of this invention includes a uterine fibroid or a collection or concentration of leiomyoma cells, which cells are the target of the present invention. The compositions of the present invention are formulations of an active agent, plus any carrier and formulary materials to which a subject""s tissue is initially exposed. An agent is a substrate that is a fibroid cell growth inhibitor. A carrier is a substance that facilitates the agent""s interaction with a transport or communication mechanism that moves substrates into the milieu of the fibroid cells. A dose is an amount of composition containing a sufficient concentration of agent to inhibit or reduce proliferation after transport into the milieu of the target cells. A communication or transport means is a mechanism by which the agent is moved from the point of the subject""s exposure to the composition into the milieu of the target cells. A vehicle is the physical packaging of the composition as administered to a subject to be treated. A delivery or release device is a xe2x80x9chardwarexe2x80x9d type of delivery vehicle.
The delivery vehicle of the present invention is any means for containing a composition comprising an agent useful for inhibiting uterine fibroid cell growth, and releasing it to enter into a communication or transport means. A transport means preferably is a natural mechanism for communicating agent substrate from the delivery vehicle into the milieu of the target cell population. Such communication means includes chemical means such as diffusion, gradient transport, etc., and biological means such as closed or preferential type circulatory means (e.g., the uterine first pass effect).
Generally, the methods of treatment of the present invention comprises: giving a dose of composition that incorporates a fibroid cell growth inhibitor (FGI) agent to a subject to be treated for uterine fibroids. The dose is delivered non-systemically by placing it as proximate as possible to the uterine fibroid cells to be inhibited.
The FGI agent in the composition of the dose is a substrate that is normally present and physiologically well tolerated in humans or an analog or derivative of such a substrate. The dose of composition contains a sufficient amount of the FGI agent such that, upon transport of the agent into the milieu of the uterine fibroid cells, the delivered amount is effective to inhibit the growth of said cells. After delivery of the dose of the composition proximate the fibroid cells, the fibroid cells are exposed to the FGI to the agent to inhibit their growth. Examples of fibroid cell growth inhibitor (FGI) agents are substrates that are a protein kinase C pathway inhibiting compound; a direct protein kinase C inhibitor; an xcex1-tocopherol, its derivatives or analogue; and a MAP kinase inhibitor. Certain thiazolidinediones have been demonstrated to effect PKC mediated pathway, in view of which makes them identified potential FGI agents. The determination of any specific identified potential FGI agent as an actual FGI agent may be accomplished according to Example 1, below.
Identified FGI agents potentially useful in the practice of the present invention include: xcex1- and xcex2-tocopherols, xcex1-tocopherol succinates, thiazolidinediones (e.g., troglitazone), bisindolemalemides, (e.g., GF109203x), U73122, and PD98059. Additionally, appropriate FGI agents include signaling molecules that effect the Protein Kinase C and MAP kinase pathways.
The composition contains an amount of the FGI agent sufficient to inhibit the growth of uterine fibroid cells upon delivery into the milieu of the fibroid. The composition may be pure FGI agent or may be a mixture of the active agent in a carrier media. The composition may be packaged in a vehicle to facilitate its delivery to a subject. Delivery vehicles adaptable by one of ordinary skill in the art for use with the present invention include: suppositories, tampons, creams, pessaries, micro-capsules and intra-vaginal drug dispensing or releasing devices as are known in the art.
The method of the present invention may be practiced in at least two primary ways, intra-vaginally and in situ. Intra-vaginal delivery is a non-invasive method of administering FGI agents. It is non-invasive in that it does not require the artificial penetration of the epithelium (skin) to accomplish delivery of the substrate to the target site. In situ delivery is a minimally invasive method in that it may be accomplished with only the puncture or the making of a small incision in the skin.
In the intra-vaginal method, the composition is delivered by inserting the composition or the vehicle carrying the composition into the vagina of a woman to be treated for uterine fibroids, proximate the uterus, and in communication with the tissue of the vaginal wall. In this method, the FGI agent is released from the composition into communication with the tissue of the vaginal wall. The release of the FGI agent from the composition depends on the nature of the composition and the vehicle, if any, used to deliver the composition. After the FGI agent is released from the composition and contacts and enters the tissue of the vaginal wall, it is transported from the vaginal tissue to the tissue of the uterus via a pathway identified as the xe2x80x9cfirst uterine pass mechanism.xe2x80x9d Bulletti et al., Human Reproduction, v12(5):1073-1079 (1997). This method may also be practiced by containing the composition in a vaginal release device, and inserting the device into the vagina of a subject to be treated for uterine fibroids proximate the uterus, as described above. The composition containing the FGI agent is released from the device according to the design of the device and into communication with the tissue of the vaginal wall. As further described above, the FGI agent is transported from the vaginal tissue to the tissue of the uterus and hence the milieu of a uterine fibroid via the xe2x80x9cfirst uterine pass mechanism.xe2x80x9d
Vehicles appropriate for carrying the composition to accomplish intra-vaginal delivery include: creams, gels, suppositories, pessaries, and intra-vaginal release devices. Such vehicles as may be inserted into the uterus directly would also be appropriate for use with the present invention.
In the in situ method, the composition is delivered by injecting it directly into the uterus of a woman to be treated, preferable proximate a fibroid to be treated. When it is desirable to deliver a large dose of FGI agent to accomplish a relatively immediate, high level effect, the composition may be injected by syringe directly into a fibroid cell mass. The location of the intended injection site may be determined by palpating the fibroid (if large enough) or by an imaging means such as sonography, laparoscopy, x-ray, MRI or the like. If desired, a more constant dosing with an FGI agent may be accomplished using in situ injection by containing or formulating the composition in a time release vehicle, such as a micro-capsule, and injecting the micro-capsules by syringe into the uterine tissue generally, or directly into the fibroid to be treated. The micro-capsule may be injected generally into the uterine tissue, but preferable would be injected proximate or directly into the uterine fibroid to be treated, to permit the controlled time release of the FGI agent directly into the milieu of the fibroid. In situ or intrauterine delivery of a FGI agent (such as by the injection of micro-capsules) into or near the leiomyoma can be accomplished under non-invasive guidance of an imaging means or by palpation, as noted above.
Basically, the system of the present invention, for inhibiting the growth or proliferation of uterine fibroid leiomyoma cells, comprises a population of uterine fibroid cells in which the growth of such cells is to be inhibited; a fibroid cell growth inhibitor agent effective to inhibit the growth of uterine fibroid cells; a vehicle for containing and delivering the agent in a controlled manner into communication with the uterine fibroid cells so that the agent can inhibit the growth of the uterine fibroid cells.